1. Field of the Invention
Aspects of the present invention relate to an organic electro-luminescent display and a method of making the same.
2. Description of the Related Art
In recent years, a variety of flat panel displays have been developed, which have lower weight and volume than cathode ray tubes. In particular, organic light emitting diode display devices have attracted public attention for having excellent luminous efficiency, luminance, and viewing angle, as well as a rapid response time.
The organic electro-luminescent display displays an image using plurality of organic light emitting diodes (OLED). An organic light emitting diode includes an anode electrode, a cathode electrode, and an organic light emission layer arranged between the anode electrode and the cathode electrode. An organic light emitting diode emits light by coupling electrons with holes.
If an electric current flowing in the organic light emitting diodes is high, the organic light emitting diodes display a high luminance. If an electric current flowing in the organic light emitting diodes is low, the organic light emitting diodes display a low luminance. Therefore, grey levels are displayed by controlling the electric current flowing in the organic light emitting diodes.
For this purpose, a larger electric current is applied, if the total brightness of one image displayed in the organic electro-luminescent display is high, as opposed to if the total brightness of one image is low. The contrast of the organic electro-luminescent display is reduced, due to a smaller apparent difference in the brightness between a high grey level and a low grey level, if one image is displayed with a higher total grey level.
Accordingly, in order to solve the above problems, some display devices use of a power supply unit that produces a large flow of high voltage electric current, which increases production costs. Also, a sudden increase in the electric current may cause a driving interruption.